Exodus 28:37

על פתיל תכלת [AND THOU SHALT PUT IT] ON A BLUE PURPLE STRING — but in another passage (Exodus 39:31) is states, “And they put upon it (upon the Plate) a string of blue purple (so that the Plate was beneath the string, not upon it as is here commanded)! Then again, it is written here, “and it (the Plate) shall be upon the mitre”, whilst further on (v. 38) it says, “And it shall be upon Aaron’s forehead”! And in the Treatise on the Slaughter of the Sacrifices (Zevachim 19a) we learn: “His (the High Priest’s) hair was visible between the Plate and the mitre, whereon he placed the Tephillin”, thus informing us that the mitre was above on the crown of the head and was not so deep that the entire head went into it right down to the forehead, and that the Plate was beneath it with a space between them. Consequently the Plate was not on the mitre as seems to be stated in this verse! But I say that (cf. Rashi on Exodus 39:31 ואומר אני וגו׳) the strings were in holes and hung from it (from the Plate) at its two ends and at its middle point, six in these three places (i. e. one string in each hole, the centre of each string resting on the bottom point of the hole, the three thus forming six). Thus, at each hole, there was one string on top of the Plate — outside it, and one inside (between the Plate and the forehead). He tied the ends of the strings, the three of them, behind the neck; it follows therefore that the length of the Plate and the strings that were at its ends together encompassed his skull. The middle string which was on its top edge bound together with the ends of the two which were at the extremities of the Plate, passed over the breadth of the head above (over the crown). Consequently it (the Plate, together with the strings) formed a kind of helmet. It is with reference to the middle string that it states, “And it (the string just mentioned in the verse; not the Plate as was assumed) shall be upon the mitre”, for he placed the Plate, with the strings already tied in this manner, upon his head as a kind of helmet passing it over the mitre, and the middle string held it (the Plate) firm so that it could not fall, and thus the Plate hung in front of his forehead and did not fall lower down. In this way all these verses find their explanation — the string being on the Plate, the Plate on the string, and the string on the mitre above (cf. Chullin 138a).

וְשַׂמְתָּ֤ אֹתוֹ֙ עַל־פְּתִ֣יל תְּכֵ֔לֶת וְהָיָ֖ה עַל־הַמִּצְנָ֑פֶת אֶל־מ֥וּל פְּנֵֽי־הַמִּצְנֶ֖פֶת יִהְיֶֽה׃

And thou shalt put it on a blue lace, that it may be upon the mitre; upon the forefront of the mitre it shall be.